Family secrets and fairy lore create a shifting reality in McMahon's unsettling novel about the disappearance of a 12-year-old girl who longed to become Queen of the Fairies. Fifteen years after Lisa goes missing, her younger brother, Sam, gets a strange phone call that leads him and his girlfriend, Phoebe, to discover a book, supposedly written by the King of the Fairies, that Lisa used as her bible to cross over, and which prompts Sam and Phoebe to meet up with Sam's cousin, Evie, to see if they can figure out what happened to Lisa. Nothing is as it seems from that moment on, and Phoebe's longtime fear of a dark man in the shadows seeps back after she discovers, in true woo-woo fashion, that she is pregnant. McMahon (Promise Not to Tell) alternates between the past and present with loads of portent and foreshadowing, creating a rural Vermont chiller with a Rosemary's Baby vibe, but even after a surprising villainess emerges and more than a few disquieting passages about Lisa are burned through, many readers will remain in the dark. (May)